Effect of Nanoemulsified and Microencapsulated Mexican Oregano (Lippia graveolens Kunth) Essential Oil Coatings on Quality of Fresh Pork Meat

Fresh meat is a highly perishable food. This work aimed to evaluate the influence of Mexican oregano (Lippia graveolens Kunth) incorporated into active coatings (ACs) spread on fresh pork meat as free (FEO), nanoemulsified (NEO), and microencapsulated (MEO) essential oil (EO), on its microbiological, physicochemical and sensory properties during 15 d at 4 ± 1 °C. Thymol and γ‐terpinene were identified in the EO. In vitro effect of 2.85 mg EO/cm2 was tested against Brochothrix thermosphacta, Micrococcus luteus, Lactobacillus plantarum, Pseudomonas fragi, and Salmonella Infantis. FEO antioxidant capacity (DPPH assay) was significantly higher than that of thymol, NEO and MEO (93.53%, 89.92%, 77.79%, and 78.50% inhibition, respectively), and similar to BHA (96.03%) and gallic acid (95.57%). FEO, NEO, and MEO ACs on meat caused growth inhibition of lactic acid bacteria (5 log population reduction) and Pseudomonas spp. (4 log reduction), whereas ≤1.5 log population reduction was observed for B. thermosphacta and Salmonella Infantis. Meat microbiota was more efficiently controlled by MEO than by FEO or NEO. ACs delayed lipid and oxymyoglobin oxidation of fresh pork meat. After 15 d of cold storage meat added with EO coatings was desirable for panelists, whereas untreated (UT) samples were undesirable. Active coatings are a significant alternative method for fresh meat preservation. Practical Application Mexican oregano (Lippia graveolens Kunth) can be incorporated into active coatings on fresh pork meat as free essential oil (EO) to promote antioxidant effect. Microencapsulated oregano EO can control the pathogen Salmonella Infantis and Brochothrix thermosphacta, while providing growth inhibition of food spoilage microorganisms (lactic acid bacteria, Pseudomonas sp.). Combination of cold storage, active coatings containing Mexican oregano EO, and vacuum packaging, can provide a protective effect against spoilage and pathogenic bacterial growth in fresh meat.